The regulation of LH/hCG receptors in testis and ovary has been further analyzed with particular reference to the control of receptor concentration by changes in the homologous hormone. Both LH and hCG were found to cause marked decreases in receptors of testis and ovary, with consequent desensitization of adenylate cyclase and steroidogenic responses to gonadotropic hormones. These studies have indicated that hormone-receptor interaction leads to receptor loss, by a mechanism that appears to involve turnover of processing of the hormone-receptor complex. BIBLIOGRAPHIC REFERENCES: Hsueh, A.J.W., Dufua, M.L., Katz, S.I. and Catt, K.J.: Gonadotropin receptors - Immunofluorescence labeling in enzyme-dispersed interstitial cells. Nature 261:710-712, 1976. Hsueh, A.J.W., Dufau, M.L. and Catt, K.J.: Gonadotropin-induced regulation of luteinizing hormone receptors and desensitization of testicular 3'-5' cyclic AMP and testosterone responses. Proc. Natl Acad Sci USA 74:592-595, 1977.